Re: [PATCH] scsi: libiscsi: use kvzalloc for iscsi_pool_init

The Lee-Man
2017-05-18T16:49:15Z

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On Wednesday, May 17, 2017 at 2:38:56 PM UTC-7, Kyle Fortin wrote:
>
> iscsiadm session login can fail with the following error:
>
> iscsiadm: Could not login to [iface: default, target: iqn.1986-03.com...
> iscsiadm: initiator reported error (9 - internal error)
>
> When /etc/iscsi/iscsid.conf sets node.session.cmds_max = 4096, it results
> in 64K-sized kmallocs per session. A system under fragmented slab
> pressure may not have any 64K objects available and fail iscsiadm session
> login. Even though memory objects of a smaller size are available, the
> large order allocation ends up failing.
>
> The kernel prints a warning and does dump_stack, like below:
>
> iscsid: page allocation failure: order:4, mode:0xc0d0
> CPU: 0 PID: 2456 Comm: iscsid Not tainted 4.1.12-61.1.28.el6uek.x86_64 #2
> Call Trace:
> [<ffffffff816c6e40>] dump_stack+0x63/0x83
> [<ffffffff8118e58a>] warn_alloc_failed+0xea/0x140
> [<ffffffff81191df9>] __alloc_pages_slowpath+0x409/0x760
> [<ffffffff81192401>] __alloc_pages_nodemask+0x2b1/0x2d0
> [<ffffffffa048f6c0>] ? dev_attr_host_ipaddress+0x20/0xffffffffffffc722
> [<ffffffff811dc38f>] alloc_pages_current+0xaf/0x170
> [<ffffffff81192581>] alloc_kmem_pages+0x31/0xd0
> [<ffffffffa048f600>] ? iscsi_transport_group+0x20/0xffffffffffffc7e2
> [<ffffffff811ad738>] kmalloc_order+0x18/0x50
> [<ffffffff811ad7a4>] kmalloc_order_trace+0x34/0xe0
> [<ffffffff8146ee30>] ? transport_remove_classdev+0x70/0x70
> [<ffffffff811e843d>] __kmalloc+0x27d/0x2a0
> [<ffffffff810c8cbd>] ? complete_all+0x4d/0x60
> [<ffffffffa04af299>] iscsi_pool_init+0x69/0x160 [libiscsi]
> [<ffffffff81465d90>] ? device_initialize+0xb0/0xd0
> [<ffffffffa04af510>] iscsi_session_setup+0x180/0x2f4 [libiscsi]
> [<ffffffffa04c5a60>] ? iscsi_max_lun+0x20/0xfffffffffffffa9e [iscsi_tcp]
> [<ffffffffa04c531f>] iscsi_sw_tcp_session_create+0xcf/0x150 [iscsi_tcp]
> [<ffffffffa04c5a60>] ? iscsi_max_lun+0x20/0xfffffffffffffa9e [iscsi_tcp]
> [<ffffffffa048a633>] iscsi_if_create_session+0x33/0xd0
> [<ffffffffa04c5a60>] ? iscsi_max_lun+0x20/0xfffffffffffffa9e [iscsi_tcp]
> [<ffffffffa048abd8>] iscsi_if_recv_msg+0x508/0x8c0 [scsi_transport_iscsi]
> [<ffffffff811922eb>] ? __alloc_pages_nodemask+0x19b/0x2d0
> [<ffffffff811e6d69>] ? __kmalloc_node_track_caller+0x209/0x2c0
> [<ffffffffa048b00c>] iscsi_if_rx+0x7c/0x200 [scsi_transport_iscsi]
> [<ffffffff81623dc6>] netlink_unicast+0x126/0x1c0
> [<ffffffff8162468c>] netlink_sendmsg+0x36c/0x400
> [<ffffffff815d2fed>] sock_sendmsg+0x4d/0x60
> [<ffffffff815d596a>] ___sys_sendmsg+0x30a/0x330
> [<ffffffff811bc72c>] ? handle_pte_fault+0x20c/0x230
> [<ffffffff811bc90c>] ? __handle_mm_fault+0x1bc/0x330
> [<ffffffff811bcb32>] ? handle_mm_fault+0xb2/0x1a0
> [<ffffffff815d5b99>] __sys_sendmsg+0x49/0x90
> [<ffffffff815d5bf9>] SyS_sendmsg+0x19/0x20
> [<ffffffff816cbb2e>] system_call_fastpath+0x12/0x71
>
> Use kvzalloc for iscsi_pool in iscsi_pool_init.
>
> Signed-off-by: Kyle Fortin <kyle.fortin-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
> Tested-by: Kyle Fortin <kyle.fortin-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
> Reviewed-by: Joseph Slember <joe.slember-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
> Reviewed-by: Lance Hartmann <lance.hartmann-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
> ---
> drivers/scsi/libiscsi.c | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
> index dd6828f..42381ad 100644
> --- a/drivers/scsi/libiscsi.c
> +++ b/drivers/scsi/libiscsi.c
> @@ -2556,7 +2556,7 @@ int iscsi_eh_recover_target(struct scsi_cmnd *sc)
> * the array. */
> if (items)
> num_arrays++;
> - q->pool = kzalloc(num_arrays * max * sizeof(void*), GFP_KERNEL);
> + q->pool = kvzalloc(num_arrays * max * sizeof(void*), GFP_KERNEL);
> if (q->pool == NULL)
> return -ENOMEM;
>
> @@ -2590,7 +2590,7 @@ void iscsi_pool_free(struct iscsi_pool *q)
>
> for (i = 0; i < q->max; i++)
> kfree(q->pool[i]);
> - kfree(q->pool);
> + kvfree(q->pool);
> }
> EXPORT_SYMBOL_GPL(iscsi_pool_free);
>
> --
> 1.7.1

Signed-off-by: Lee Duncan <lduncan-IBi9RG/b67k@public.gmane.org>

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